/**
* Module dependencies.
*/
var Transport = require('../transport');
var parser = require('engine.io-parser');
var util = require('util');
var debug = require('debug')('engine:ws');
/**
* Export the constructor.
*/
module.exports = WebSocket;
/**
* WebSocket transport
*
* @param {http.IncomingMessage}
* @api public
*/
function WebSocket (req) {
Transport.call(this, req);
var self = this;
this.socket = req.websocket;
this.socket.on('message', this.onData.bind(this));
this.socket.once('close', this.onClose.bind(this));
this.socket.on('error', this.onError.bind(this));
this.socket.on('headers', onHeaders);
this.writable = true;
this.perMessageDeflate = null;
function onHeaders (headers) {
self.emit('headers', headers);
}
}
/**
* Inherits from Transport.
*/
util.inherits(WebSocket, Transport);
/**
* Transport name
*
* @api public
*/
WebSocket.prototype.name = 'websocket';
/**
* Advertise upgrade support.
*
* @api public
*/
WebSocket.prototype.handlesUpgrades = true;
/**
* Advertise framing support.
*
* @api public
*/
WebSocket.prototype.supportsFraming = true;
/**
* Processes the incoming data.
*
* @param {String} encoded packet
* @api private
*/
WebSocket.prototype.onData = function (data) {
debug('received "%s"', data);
Transport.prototype.onData.call(this, data);
};
/**
* Writes a packet payload.
*
* @param {Array} packets
* @api private
*/
WebSocket.prototype.send = function (packets) {
var self = this;
for (var i = 0; i < packets.length; i++) {
var packet = packets[i];
parser.encodePacket(packet, self.supportsBinary, send);
}
function send (data) {
debug('writing "%s"', data);
// always creates a new object since ws modifies it
var opts = {};
if (packet.options) {
opts.compress = packet.options.compress;
}
if (self.perMessageDeflate) {
var len = 'string' === typeof data ? Buffer.byteLength(data) : data.length;
if (len < self.perMessageDeflate.threshold) {
opts.compress = false;
}
}
self.writable = false;
self.socket.send(data, opts, onEnd);
}
function onEnd (err) {
if (err) return self.onError('write error', err.stack);
self.writable = true;
self.emit('drain');
}
};
/**
* Closes the transport.
*
* @api private
*/
WebSocket.prototype.doClose = function (fn) {
debug('closing');
this.socket.close();
fn && fn();
};